1. Field of the Invention
The present invention relates to a slide fastener and more particularly to a separable type water-resistant slide fastener having a separable bottom-end-stop assembly.
2. Description of the Prior Art
There are known a number of water-resistant slide fasteners. One example is shown in Japanese Laid-open Patent Publication No. 59-111705, wherein a water-resistant slide fastener stringer comprises a water-resistant stringer tape and a pair of upper and lower rows of synthetic resinous coupling elements mounted on opposite surfaces of the stringer tape along a longitudinal marginal portion thereof, the upper and lower coupling element rows being engageable with a pair of corresponding coupling element rows, respectively, of the like companion stringer, to thus cause a contact edge of the stringer tape engage with the corresponding contact edge of the companion stringer tape, thereby ensuring a water-tightness between the two fastener stringers.
Heretofore, there have existed, indeed, water-resistant slide fasteners having such water-resistant fastener stringers of the non-separable type or the type of having both fastener stringers not separated at their lower ends. However, there has been produced no water-resistant slide fasteners of the separable type or the type that is equipped with a separable bottom stop assembly so that the fastener stringers can be fully separated from their lower ends. This is attributable to there having remained various problems in making separable type slide fasteners of such water-resistant fastener stringers.
Firstly, since the water-resistant stringer tapes are literally made of water-resistant material such as natural or synthetic rubber or other elastomeric synthetic resin and hence considerably rigid, it is very difficult if not impossible to manipulate the separable bottom-end-stop assembly attached to such rigid water-resistant stringer tapes. Particularly, since the water-resistant stringer tapes are too rigid to bend easily, an insert pin member secured to one of the stringer tapes cannot be inserted into a socket member secured to the other stringer tape easily and smoothly.
Secondly, since two or upper and lower fastener element rows mounted on one fastener stringer instead of a single fastener element row must be brought into interdigitating engagement with the two corresponding upper and lower fastener element rows on the other or companion stringer and that simultaneously, this manipulation is very difficult. There is a great difficulty in placing the lowermost elements of one pair of coupling element rows on one stringer into correct engagement with the corresponding lowermost elements of the other pair of coupling element rows on the other stringer; failing which, even if an attempt is made to lift a slider, the slider will never start to ascend for engagement of the coupling element rows. Granting that the lowermost elements on the one stringer engaged correctly with the corresponding element on the other stringer, considerable force would be necessary to start to lift the slider along the coupling element rows.
Thirdly, existence of the two or upper and lower coupling element rows on the opposite surfaces of the stringer tape instead of a single coupling element row on any one surface thereof gives naturally rise to the slider becoming the greater in thickness, so that the slider is apt to be inclined relative to the socket member. As a result, it is very difficult to thread the insert pin member through the thus inclined slider into the socket member.